PCIe To M.2 Adapter With PoE Function For Raspberry Pi 5, Supports NVMe Protocol M.2 Solid State Drive, High-speed Reading/Writing, Supports 802.3af/at network standard, Raspberry Pi 5 PoE HAT
Not quite, Watts are a function of Volts x Amps, in the case of your switch it supports 802.3at as a standard and will be enough to power a Pi5 with this hat.
The tallest component on this HAT when connected to the Pi 5 is the headers, which I measured to be approximately 10mm. I tested the HAT with a Pi 5 inside the case you linked, and it fits well!
That heatsink, while close, will be slightly too tall to fit between his PoE HAT and the Pi 5. The inbuilt fan on the PoE hat seems to do an adequate job of keeping everything cool.
If you are looking for a solution that includes a heatsink, maybe a setup using this alternative PoE HAT for the Pi 5 would work better for you as it has a lot more room to fit some heatsinks on the Pi.